The present invention relates generally to intake structures for internal combustion engines, and more particularly, to a vane which is incorporated in the intake passage of internal combustion engines for producing advantageous swirl in the combustion chambers of the engine during operation.
In the field of internal combustion engines, it is known that, if the intake gas induced into a combustion chamber is provided with a swirling motion, the resulting turbulence assists the propagation of flame in the combustion chamber increasing the speed of flame propagation, thereby improving the performance of the engine. In additions the anti-knock and driving characteristics of the engine, and the quality of the exhaust emissions thereof, are improved.
Conventionally, the inlet port of an internal combustion engine, especially a gasoline engine, is formed so as to minimize the resistance to the flow of intake gases and thereby increase the volumetric efficiency and maximum output power of the engine at high load operation. When such an internal combustion engine is operating at high load, although the flow or suction resistance of the inlet port is low, sufficient turbulence and swirl is caused in the combustion chamber for the flame propagation speed to be kept at an acceptable level.
However, during low and medium load operation, in which the amount of inlet gases is relatively low, good swirl and turbulence of the inlet gases does not occur, due to the low flow resistance of the inlet port, and because the velocity of the inlet gas entering the combustion chamber from the inlet port is low. Thus combustion speed is sometimes not high enough, and, especially if the engine is operating in a lean mixture condition, or is provided with a substantial quantity of exhaust gas recirculation, good operating performance of the engine may be lost.
The present invention results from the realization that, if the flow of inlet gases through the inlet port is directed past the side of the inlet port which is remote from the central axis of the power cylinder, i.e. closest to the circumference of the power cylinder, especially during low and medium load operation of the engine, swirl and turbulence in the combustion chamber would be advantageously improved, and combustion speed would be increased.
It is, therefore, an object of the present invention to provide an apparatus in the inlet passage of an internal combustion engine by which the mixture gas is directed into the combustion chamber as a flow particularly directed past the part of the edge of the inlet port which is remote from the central axis of the power cylinder of the engine, particularly in low and medium load operation of the engine.